<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>css过渡效果</title>
    <style>
div{
    width: 200px;
    height: 200px;
    background-color: pink;
    margin: 200px auto;
    /*transition: all 2s;*/
    transition-property: width;
    /*指定过渡是时间，以秒为单位*/
    transition-duration: 2s;

    /*设置过渡是的速度曲线  贝塞尔*/
    border-radius: 50%;
}
div:hover{
    width: 400px;
    height: 400px;
    transition-property: height;
    transition-duration: 2s;
    background-color: saddlebrown;
    border-radius: 50%;

}
    </style>
</head>
<body>
    <div></div>
</body>
</html>